1. Field of the Invention
The present invention relates to machines for bonding resawn split shakes to a backing for producing prefabricated shake panels.
2. Prior Art
It is known that thermosetting glue between two articles held in engagement under pressure can be set quickly by dielectric heating to bond the articles together. However, formation of a bond of uniform strength by dielectrically heating thermosetting glue requires that the articles be held together with substantially uniform pressure. Consequently, it has been difficult to obtain uniformly strong bonds between resawn split shakes and a backing because of the difficulty in holding the shakes against the backing under the same pressure. Such difficulty has resulted both from the variation in shake thickness and from the irregularity of the shake split surfaces. Previously shakes have been bonded to backing pieces while being conveyed as shown in U.S. Pat. No. 3,068,920, but the joint made has not been entirely satisfactory.